This invention relates to a process for the production of polymeric alkali metaol silicate glass. This product has good strength, elasticity, wear resistance and will not support a flame. It may be utilized as a coating agent as adhesive, as binders, as a laminating agent, for molding useful products and for film producing.
In U.S. Pat. Application, no. 057810, filed 06-01-87, a flexible glass was produced whereas in this invention a much stronger polymeric alkali metal silicate glass is produced by polymerizing the alkali metal silicate by using multiple steps of controlled hydration and dehydration. The production of alkali metal silicate film is known in the Arts. The films produced from the known aqueous alkali metal silicate solution are brittle, had poor strength and develops micro-cracks while drying. On pages 122 and 123 of "The Chemistry of Silica" by Ralph K. Iler, published in 1979 by A. Willy-Interscience Publication, New York, Iler discusses sodium silicate solutions used as adhesives and points out that the film formed by drying the water from the sodium silicate produces a film which is brittle and has micro-cracks that lower the strength of th dried film.
I have discovered that a strong, somewhat elastic polymeric alkali metal glass product which may be rigid or flexible, can be produced by multiple steps of controlled limited hydration and dehydration of a powdered alkali metal silicate glass with a silicon dioxide:alkali metal oxide ratio of 1:1 to 3.9:1, preferably a ratio of 2.0:1 to 3.3. The polymeric alkali metal glass is then mixed with water until a suspension and/or a solution is produced. The excess water is then evaporated from the aqueous suspension or solution thereby producing a polymeric alkali metal silicate glass product. The silicon dioxide:alkali metal oxide ratio of the aqueous polymeric alkali metal silicate glass suspension and/or solution may be increased up to about 25:1 by the addition of oxidated silicon compounds such as hydrated silica, aqueous suspended silica, precipitated silica, fumed silica, silicic acid, polysilicic acid, etc. The amount of oxidated silicon compounds used is limited by the amount of water present.